1. Field of the Invention
The present invention relates to drinking mugs and cups that are provided with a closure to prevent spilling of the contents, such as when used during traveling in a vehicle. More .specifically, the invention is directed to such a mug or cup when a closure valve is provided to control dispensing of the contents of the cup or mug.
2. Related Art
A drinking cup with a laterally actuated valve is known from U.S. Pat. No. 4,276,992, in which a drinking cup is provided with a cover for closing its top opening. This cover is secured to the cup by a bayonet-type connection and has an opening through which the contents of the cup may be dispensed. To prevent spillage through the opening of the cover, a spring-loaded valve is mounted on the cover, and this valve is designed to be operable by the thumb of a hand holding the handle of the cup. However, because the opening of the cover is positioned at a 90 degree angle with respect to the handle of the cup, a left-handed person cannot use a cup and cover assembly that is designed right-handed users and vice versa. Furthermore, the provision of only the one valved opening does not insure effective venting of the cup interior during dispensing of its contents, resulting in potential surges as air is vented in through the single opening, due to the creation of a partial vacuum as the contents are discharged from the opening, a characteristic which can have unpleasant consequences, particularly when the cup contains a hot beverage.
In U.S. Pat. No. 4,121,731, a top enclosure for children's drinking vessels is shown which has a pair of handles, one at 90 degrees clockwise and one at 90 degrees counterclockwise relative to the drinking opening of the top enclosure. However, this device is designed so that one can "drink from the drinking vessel only when the handles on opposing sides of the vessel are depressed," so that the contents will not spill if the vessel drops on the floor and lands on a handle. However, besides the awkwardness and unattractiveness of having two handles, such a drinking vessel does not permit one-handed use, whether it be right-handed or left-handed, and thereby is unsuitable for adult usage.
Thus, there is a need for a spill-proof drinking mug which has a valved drinking opening which can be used in one hand and is not limited to use by a specific hand of the user.